Atopic dermatitis (AD) is a skin condition characterized by a rash and itching, resulting from skin inflammation. Ivarmacitinib is an approved medication for treating AD.

This study assessed the efficacy and safety of switching to the JAK1 inhibitor ivarmacitinib over 16 weeks in patients with moderate-to-severe atopic dermatitis and inadequate response to IL-4Rα inhibitors under real-world conditions.

It is expected that there will be no additional burden for participants in this trial.

Inclusion Criteria:

• Aged between 18 and 75 years.
• Patients diagnosed with moderate-to-severe atopic dermatitis and treated with IL-4Rα inhibitors according to standard regimens for a minimum of 12 weeks.
• Meeting any of the following disease activity criteria: EASI ≥16, WI-NRS ≥4.

Exclusion Criteria:

• Treatment with other JAK inhibitors, including topical formulations, within one week before enrollment.

• Subjects with clinically significant diseases of the heart, liver, kidney, or other major organ systems.

• Subject has any of the following abnormalities in clinical laboratory tests at screening, as assessed by the study-specific laboratory and confirmed by a single repeat, if deemed necessary:

  a. Absolute lymphocyte count of <0.50 x 10^9 /L (<500/mm3);b. Absolute Neutrophil Count (ANC) of <1 X 10^9/L (<1000/mm3);c. Hemoglobin level < 80 g/L.

• Subject with a prior history of thromboembolic events, including deep vein thromboses (DVT), pulmonary embolism, cerebrovascular accidents and those with known inherited conditions that predispose to hypercoagulability.

• Presence of an active severe acute or chronic bacterial, fungal, or viral infection requiring systemic therapy.

• Subjects with active tuberculosis or known active hepatitis B and/or hepatitis C infection.

• Subject has any malignancies or has a history of malignancies with the exception of adequately treated or excised non-metastatic basal cell or squamous cell cancer of the skin, or cervical carcinoma in situ.

• Pregnant or breastfeeding women, or women of childbearing potential who are unwilling to use contraception.